1. Field of the Invention
The present invention generally relates to a surgical instrument and staples for applying purse string sutures to human tissue and, more particularly, to a surgical instrument and method in which a purse string suture is secured to human tissue by a plurality of staples. In addition, this invention relates to a surgical staple for securing a purse string suture to human tissue in which the staple body is adapted to be slidably attached to the purse string suture.
2. Description of the Prior Art
In the prior art, it is known to use a purse string suture to close a tubular section of tissue, e.g., intestinal tissue, prior to the performance of an end-to-end anastomosis with a circular suturing instrument. The purse string suture is attached to a surgical needle which is used by a surgeon to manually stitch the purse string suture about the periphery of the tubular section of tissue. After the purse string suture is stitched to the tissue, the ends of the purse string suture are pulled to tighten the stitches and draw the tissue together. Then, the purse string suture is wrapped and tightened about the tubular section of tissue. In the manual stitching of the purse string suture, it is difficult to obtain uniform penetration of the purse string suture into the tissue. It is also difficult to obtain stitches which are uniform in length and are evenly spaced apart. As a result, some of the stitches may rip away from the tissue when the ends of the purse string suture are pulled.
Purse string suture devices are known in the prior art which comprise a pair of serrated tissue clamping jaws provided with teeth for clamping the tissue to be sutured therebetween. Such devices include needle passages which extend through the teeth on each jaw for receiving a needle attached to a suture to be threaded through the tissue. In use, the tissue to be sutured is clamped between the jaws and the needle is manually passed through the needle passages in both jaws to thread the suture through the tissue. Thereafter, the jaws are opened and the purse string suture is tightened and wrapped to draw the tissue together. Because the tissue may be gathered unevenly between the jaws, it is sometimes difficult to obtain uniform penetration of the needle and suture into the tissue. Thus, when the ends of the purse string suture are pulled to gather the tissue together, there is a tendency for at least some of the stitches formed by the purse string suture to rip away from the tissue. Also, it is possible that some of the stitches may extend through both walls of the tubular section of tissue with the result that the tissue is not uniformly drawn together when the ends of the purse string suture are pulled to draw the tissue together.
In the prior art, it has been proposed to provide purse string suture devices which utilize a plurality of staples for applying purse string sutures to human tissue. Both anvil carrying devices and anvilless devices have been proposed for applying the staples and the purse string sutures to the tissue.
For example, U.S. Pat. No. 4,749,114 discloses a purse string applicator which includes an anvil carrier with a plurality of anvils for insertion in a tubular section of tissue and a pair of staple cartridges disposed on opposite sides of the anvil carrier. Each cartridge has a row of staples and the purse string suture extends across each row of staples. The applicator includes a pair of pushers each having a plurality of pusher fingers for driving the staples from the cartridges through the tissue against the anvils of the carrier. The staples in each row are deformed and secured to the tissue and the purse string suture is slidably retained between the staples and the tissue.
In addition, U.S. Pat. No. 4,821,939 discloses an anvilless surgical stapler for applying purse string sutures to human tissue. The stapler includes a pair of staple cartridges each having a plurality of openings for receiving a plurality of surgical staples. The cartridges include opposed projections which define grooves at both ends of the cartridges to receive a purse string suture. Each cartridge includes a pair of staple forming lips which define an outlet of lesser width than the openings. Each cartridge includes a plurality of pushers for driving the staples from the openings through the outlets and into the tissue clamped between the cartridges. As the staples are expelled from the openings, the lips deform the staple legs inwardly toward each other to penetrate into and grip the tissue. The purse string suture is located underneath each staple and is thereby attached to the tissue.
In the above examples, the purse string suture is located underneath the staples and is retained against the tissue by the staples. Consequently, when the ends of the purse string suture are pulled by a surgeon to draw the tissue together, there is some resistance to movement of the purse string suture relative to the staples and tissue. Thus, it is possible that some portions of the tissue may not be tightly drawn together by pulling on the ends of the purse string suture.
Accordingly, it is desirable to provide a surgical staple for securing a purse string suture to human tissue which does not clamp the purse string suture against the tissue. Also, it is desirable to provide a surgical staple for securing a purse string suture which presents minimal resistance to the movement of the purse string suture after the staple is secured to the tissue. In addition, it is desirable to provide a surgical staple for securing a purse string suture in which the staple body is slidably attached to the purse string suture.
Further, it is desirable to provide a method for securing a purse string suture to human tissue by a plurality of staples which are slidably attached to the purse string suture and present minimal resistance to the movement of the purse string suture relative to the tissue. Also, it is staple cartridge in which the purse string suture can be slidably attached to the surgical staples prior to the operation of the instrument to secure the staples and the purse string suture to the tissue.